Download Leafy Spurge - Langlade County

Leafy Spurge
Euphorbia esula
Leafy Spurge, a member of the Spurge Family, is legally
classified as a noxious weed in nineteen states, including
Iowa, Minnesota, and Wisconsin. Landowners in these states
are required to eradicate it. Leafy Spurge is a deep-rooted
Eurasian perennial that can dramatically reduce the economic
productivity and biological diversity of grasslands. It can
reduce the productivity of grazing land by 50 to 75 percent
because cattle and horses will not eat it. Leafy Spurge
currently inhabits about 3,000,000 acres of rangeland in the
United States with the heaviest concentrations in the northern
Great Plains, particularly North Dakota. In just four states,
the economic losses from Leaf Spurge exceed $100 million
annually.
Leafy Spurge out competes other vegetation by beginning
growth early in the spring, shading out competitors, and
taking more than its share of moisture and nutrients from the
soil. It also appears to produce chemicals that interfere with
the growth of other plant species. In natural areas, Leafy
Spurge destroys wildlife habitat by displacing native grasses
and forbs in only a few years after its introduction.
First recorded in the United States in 1827, Leafy
Spurge may have arrived here accidentally as a
contaminant in agricultural seed or intentionally as
an ornamental plant.
Habitat: Open areas, but tolerates partial shade;
rangeland, roadsides; prairies, savannas, gravel pits,
damp to dry soils; most aggressive on semiarid
sites.
Leaves: Simple (meaning that it is not divided into
sections); alternate (meaning that the leafs come off
of the stem alternately); long; narrow; 0.25 inches
wide; bluish green; usually pointed and drooping
with smooth margins; have petioles (stems).
Flowers: Very small; green; petals fused into
a cuplike structure; surrounded beneath by
prominent bracts; bloom begins around midJune, about two weeks after bracts appear,
and continues to the end of July; some plants
continue to bloom into fall; produce large
amounts of pollen and nectar.
Bracts: The most colorful and conspicuous
part of the plant; large; yellow-green; heartshaped; petal-like; paired; seven to ten are
borne in umbels at the tops of stem; open
late May or early June.
Seeds: Oblong; gray-brown; smooth;
produced in three-celled capsules (one seed
per cell); capsules expel seeds passively in
mid to late July, or explode open dispersing
seeds up to 15 feet away; can produce more
than 200 seeds per plant; high germination
rate with most seeds germinating within the
first two years; typically germinate late May
to early June but germination can occur
throughout the growing season if there is
adequate moisture; remain viable up to eight
year; spread by wildlife, humans, and water.
Stems: Erect; branched at top; non-woody;
hairless; shoots emerge in late March; grow
rapidly in May and June: can reach
densities of up to 1,800 stems per square
yard.
Saps: Milky white, sticky (latex); seeps
from plant when any part is cut or torn;
can help in identification, although it is
present in all species of the Spurge
Family.
Roots: Woody; tough; brown; pink buds
develop new rots or stems; from a dense
network to 12 inches deep; taproots teach
up to 15 feet deep; rhizomes can spread 35
feet laterally; vegetative growth along
rhizomes and root crowns is the primary
method of expansion into undisturbed
area; root reserves enable plants to recover form most
damage; very persistent; if foliage is destroyed, roots
will generate new shoots.
Control: No mechanical control methods have proven
effective on Leafy Spurge. Hand pulling, digging,
and tilling succeed only if the entire root system is
removed. The number of plants may actually increase
if any root fragments remain in the soil.
Burning has not been very effective for Leafy Spurge
control. In areas dominated by Leafy Spurge, there is
little fuel (fry grasses, sedges, or leaf litter) and fires,
therefore do not burn hot enough to kill the plants.
Studies indicate that while spring burning may
decrease seed germination, it also stimulates leaf
production.
Weekly mowing can reduce Leafy Spurge seed
production, but does nothing to limit the spread of the
rhizomes.
Imazapic is a selective herbicide that has been
effective on Leafy Spurge. It may harm cool-season
grasses, but warm-season prairie grasses, such as Big
and Little Bluestem, Indiangrass, and Sideoats
Grama, tolerate its use. Imazapic may leach into
groundwater on sandy soils, especially where the
water tale is shallow. Check with local cooperative
extension soil experts before using this product.
Imazapic should be applied in the fall before a killing
frost.
Experiments in southern Wisconsin show that
the combination of a controlled burn in the
spring followed by a foliar application of
fosamine after Leafy Spurge plants have
resprouted and begun blooming (June-July) is
an effective control measure. Using this
method, control was achieved one year after the
chemical application, although follow up
treatments were necessary for three to four years
to kill plants germinating from the seedbank.
2,4D amine plus glyphosate can be used to treat
small patches of Leafy Spurge but is
nonselective, requires repeated
application, and has poor long-term
control.
Biological Control: The United
States Department of Agriculture
has done extensive experiments
involving six insects, including flea
beetles of the genus Aphthona, to
help control Leafy Spurge. Results
thus far have been encouraging. It
is important to match the various
beetles with their appropriate
habitat requirements. These
beetles are available in most states
with spurge infestations. Persons
interested in releasing them may be
able to collect extra beetles at sites
where releases have been done
several years previously. For more
information, contact your state
invasive plant control coordinator or
the USDA’s Team Leaf Spurge at
www.team.ars.usda.gov/index.html
Angora goats and Targhee sheep like
to eat Leafy Spurge flowers, thereby
reducing seed production. In native
prairies, grazing is most helpful in
the spring when the majority of
native grasses are still dormant.
Sheep and goats are generally less
costly to use then chemical control
measures but do not limit the spread
of Leafy Spurge by rhizomes.
Ranchers who raise only cattle
should consider stocking goats and
sheep if they have an extensive
infestation of Leafy Spurge.
Leafy Spurge has infested over 1.2 million acres of rangeland in North Dakota alone, resulting in an estimated annual loss of
nearly $75 million.
Annual economic impacts of Leafy Spurge infestation on grazing and wildlands in Montana, North Dakota, South Dakota, and
Wyoming are about $129,000,000.
Because of Leafy Spurge, ranchers have had to abandon more than one million acres that could have supported 90,000 cattle.
In the mid 1980’s, a 1.360 acre ranch in Klamath County, Oregon, was abandoned due to nonproductively caused by Leafy
Spurge. It was later purchased at an auction in 1988 for 17% of the value it would have sold for otherwise.
Leafy Spurge is poisonous to cattle and causes severe eye irritation and possibly blindness in humans.